The scope of activities: Design, delivery, supply and assembly of two new specialist gantry cranes with the lifting capacity of Q=6,3t + 6,3t and span of L=28500mm, each powered by bus bars. Replacement of gantry crane rails with the length of L=90000mm each. The new track was built of gantry crane rails fixed with the use of a flexible system of rail fixing, which extends failure-free operation of gantry cranes and track durability to maximum. Disassembly of old gantry crane existing in the facility. The works were conducted in very difficult conditions above electrolysers.